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Browsing by Author "Pereira, Leonel"

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  • The antifungal activity of extracts of Osmundea pinnatifida, an edible seaweed, indicates its usage as a safe environmental fungicide or as a food additive preventing post-harvest fungal food contamination
    Publication . Silva, Paulo; Fernandes, Chantal; Barros, Lillian; Ferreira, Isabel C.F.R.; Pereira, Leonel; Gonçalves, Teresa
    In the present work, we explored the antifungal activity of the wild edible seaweed Osmundea pinnatifida (Rhodophyta) collected from the Portuguese coast, which is used as a food seasoning in Scotland, Ireland and Portugal. We performed a sequential extraction of the seaweed components with methanol, dichloromethane and n-hexane. These extracts showed an antifungal activity against Alternaria infectoria and Aspergillus fumigatus. The n-hexane fraction of the seaweed inhibited the sporulation of Alternaria infectoria at 30 μg mL −1 and induced a statistically significant decrease in β-glucan content. Furthermore, liquid cultures of Aspergillus fumigatus supplemented with 10 μg mL −1 of the n-hexane fraction showed abnormal conidiophores, completely devoid of phialides and conidia associated with a decrease of 18.3% in the chitin content. The n-hexane fraction analysis by GC-MS revealed that it includes palmitic acid (29.6%), phytol isomer 1 (12.8%), oleic acid (9.6%), stearic acid (6.2%) and D-(−)-tagatofuranose (4.1%), among other compounds present at lower concentrations. The present study reveals Osmundea pinnatifida as a promising source of biologically active compounds inhibiting fungal growth and conidiation, the main dispersal mechanism of filamentous fungi as Aspergillus fumigatus and Alternaria alternata, revealing its utility both as an environmental fungicide against fungal diseases and as a food preservative against fungal post-harvest food contamination.
    2018Journal article Open access Show more
  • Bioproducts from seaweeds: a review with special focus on the Iberian Peninsula
    Publication . Cardoso, Susana M.; Carvalho, Loic G.; Silva, Paulo J.; Rodrigues, Mara Sofia; Pereira, Olívia R.; Pereira, Leonel
    Seaweeds, i.e. macroalgae that occupy the littoral zone, are a great source of compounds with diverse applications; their types and content greatly determine the potential applications and commercial values. Algal polysaccharides, namely the hydrocolloids: agar, alginate and carrageenan, as well as other non-jellifying polysaccharides and oligosaccharides, are valuable bioproducts. Likewise, pigments, proteins, amino acids and phenolic compounds are also important, exploitable compounds. For the longest time the dominant market for macroalgae has been the food industry. More recently, several other industries have increased their interest in algal-derived products, e.g. cosmetics, pharmaceuticals and more recently, as a source of feedstock for biorefinery applications. This manuscript reviews the chemical composition of dominant macroalgae, as well as their potential added-value products and applications. Particular attention is devoted to the macroalgal species from the Iberian Peninsula. This is located in the Southwest of Europe and is influenced by the distinct climates of the Mediterranean Sea and the Atlantic Ocean, representing a rich spot of marine floral biodiversity.
    2014Journal article Restricted access Show more